The invention relates to a device for stabilizing the two lower steering arms of a tractor. The arms are actuatable by a hydraulically operated power lever. The lever has a side strut per lower steering arm. Each side strut includes a first single-acting hydraulic cylinder. The cylinder has a switching assembly which enables the two first single-acting hydraulic cylinders of the side struts to be connected to the hydraulically operated power lever. The connection has a mechanism for jointly separating the two first single-acting hydraulic cylinders hydraulically from the power lever. Also, a control establishes the connection as soon as a settable pivot position of the lower steering arms has been achieved.
In DE 195 37 555 A1, for example, the supply of the hydraulic cylinders of the side struts takes place in parallel with the supply of the hydraulic power lever. The hydraulic power lever adjusts the lower steering arms. This means that the lower steering arms are centered centrally as a function of the lifting force and position. Stabilization only takes place while the lower steering arms are being lifted. The position switch ensures that, during the lowering operation, the hydraulic cylinders of the side struts and the hydraulic power lever are jointly connected to the return line. When work is carried out on a slope, the resulting downward-directed forces cause the attached implement to assume an inclined position. Furthermore, the lower steering arms cannot be set or cannot be reliably set to the respective dimension of spread. This is due to the fact that the hydraulic cylinders cannot apply an effective force to the lower steering arms while being raised unless an implement is received at the lower steering arms.